Strapping machine

ABSTRACT

A strapping machine for binding an object by providing plastic strap forming a loop having a supply portion and the leading end thereof overlapping. Tensioning and feeding mechanism, strapgripping mechanism, strap-severing mechanism, sealing mechanism, strap-gathering mechanism, and seal-feed mechanism are provided.

Umted States Patent 1151 3,636,861 Weller 1 Jan. 25, 1971 STRAPPINGMACHINE 3,447,447 6/1969 Rutty ..100/4 3,269,300 8/1966 Billett Cl 21]...100/33 X 3,470,s 14 10/1969 Tschappu 1, 100/4 [73] Assignees lnterlakeSteel Corporation, Chicago, Ill. I

. Primary Examiner-Billy J. W1lh1te Flledi P 20, 1970 Attorney-Prangley,Clayton, Mullin, Dithmar & Vogel 21 A LN 30006 i 1 PP 1 57 ABSTRACT [52]U Cl. 3 100/4 100/26 100/30 A strapping machine for binding an object byproviding plastic 160/33 strap forming a loop having a supply portionand the leading [51] h" Cl B65, 13/02 end thereof overlapping.Tensioning and feeding mechanism, [58] Fieid 30 32 33 strap-grippingmechanism, strap-severing mechanism, sealing b /3 5 mechanism,strap-gathering mechanism, and seal-feed mechanism are provided. [5 6]Rem-wees Cited 23 Claims, 15 Drawing Figures UNITED STATES PATENTS3,139,813 7/1964 Hall et al ..l00/4 I70 I 16/ I .1

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6/0 "i; 1 6/ l I 8 \6/ 2 I288 1 79 9 l 1 m 79 S 305 3/0 T304 1t: 05 80aI A Vfi iw L J I 302 I68 30/ 304 [67 E 1 1 1 z l i 43 1 i H||| r 1' i gll l 1 1 1 r B 1 55 42 L 1,, I 1 I O V w o 169 13 O 47PATENTEUJANZSI'SYZ 3.636.861

SHEET 1 UF 6 4 INVENTOR 85 78a FRANK c. WELLER ATTYS.

PATENTED JAN251972 SHEET 3 [1F 6 STRAPPING MACHINE In operation, as theplastic strap is fed around the object, a seal is positioned within thesealing mechanism and after the leading end of the strap enters thestrap-gathering mechanism, the strap-tensioning and gripping mechanismsare simultaneously actuated to grip the leading end of the strap andtension the strap by withdrawing the supply portion thereof, thereafterthe strap-sealing mechanism is actuated and at the completion of thesealing, the tension in the supply portion of the strap is released andthe strap shearing mechanism is actuated to shear the plastic strap andprovide a cleanly severed leading end of the strap and a cleanly severedfree end of the strap.

This invention relates to an improvement in a strapping machine of thetype disclosed in US. Pat. No. 3,139,813 issued July 7, 1964 to Hall etal., the disclosure of which patent is incorporated herein by reference.More particularly, this invention relates to an improved strappingmachine for use with plastic strap and still more particularly to usewith polypropylene plastic strap.

It is an important object of the present invention to provide astrapping machine for applying a plastic strap around an object, thestrapping machine comprising strap-gripping means for holding theleading end of the strap encircled about the object and overlapping asupply portion of the strap, tensioning means for tensioning the loop ofstrap by withdrawing the supply portion of the strap relative to theleading end of the strap, sealing means for securing together theleading end of the strap and the adjacent supply portion of the strap toprovide a seal joint therebetween, control means for the tensioningmeans responsive to completion of the operation of the sealing means forreleasing the tension in the supply portion of the strap, andstrap-severing mechanism for severing the supply portion of the strapadjacent to the seal joint after the tension in the strap has beenreleased, whereby to provide a cleanly severed free end of the strapadjacent to the seal joint and to provide a cleanly severed leading endof the strap on the supply portion thereof.

Another object of the present invention is to provide a strappingmachine of the type set forth in which a fluid motor is provided foroperating the strap-severing mechanism and control mechanism is providedfor the fluid motor responsive to release of tension in the supplyportion of the strap for operating the motor.

Another object of the present invention is to provide a strappingmachine of the type set forth in which the tensioning means includefirst and second cooperating drive drums positioned to have the supplyportion of the strap passing therebetween and motor means for drivingone of the first and second drive drums to supply strap to form a loopencircled about the object and for tensioning the loop of strap bywithdrawing the supply portion of the strap relative to the leading endof the strap.

Another object of the present invention is to provide a strappingmachine of the type set forth in which there is provided controlmechanism for the sealing means responsive to a predetermined tension inthe loop of strap for activating the sealing means.

Still another object of the present invention is to provide a strappingmachine of the type set forth in which there is provided a bladeoverwhich the strap passes, the blade having a portion with transversegrooves formed therein and gripping jaws for forcing the material of thestrap into the grooves to hold the strap taut during the operation ofthe tensioning means and a movable strap shear means for coactingagainst the blade for severing the strap.

A further object of the present invention is to provide a strappingmachine of the type set forth in which there is provided a first fluidmotor for operating the strap-gripping means and the tensioning meansfor causing simultaneous actuation of the tensioning means and thestrap-gripping means, a second fluid motor for operating the sealingmeans, a third fluid motor for operating the strap-severing mechanism tosever the supply portion of the strap and control mechanism for thethird fluid motor responsive to release of tension in the supply portionof the strap for operating the third fluid motor.

The invention, both as to its organization and method of operation,together with further objects and advantages thereof, will best beunderstood by reference to the following specification taken inconnection with the accompanying drawings in which:

FIG. I is a perspective view of a parcel or package provided with abinder strap having a sealed joint therein as it would appear afterbeing applied with the apparatus of this invention;

FIG. 2 is a perspective view of a sealed joint as applied by theapparatus of this invention to the overlapping strap ends of a straploop encircled about a package;

FIG. 3 is a perspective view of a channel-shaped seal employed with theapparatus of this invention;

FIG. 4 is a side elevational view of the strapping machine of thepresent invention;

FIG. 5 is an enlarged side elevational view of a part of the machineshown in. FIG. 4;

FIG. 6 is a sectional view taken along line 6-6 of FIG. 5 particularlyshowing the strap-shearing mechanism;

FIG. 7 is a sectional view taken along line 7-7 of FIG. 5 particularlyshowing the strap-gripping mechanism;

FIG. 8 is a sectional view taken along line 88 of FIG. 5 particularlyshowing the strap-sealing and shearing mechanism;

FIG. 9 is a sectional view taken alone line 9-9 of FIG. 4 particularlyshowing the tensioning mechanism;

FIG. 10 is a diagrammatic view of the operation of the machine of thisinvention showing the strap encircling the object to be wrapped;

FIG. 11 is a diagrammatic view of the operation of the machine of thisinvention showing the strap gripped, under tension and the seal jointformed;

FIG. 12 is a diagrammatic view of the operation of the machine of thisinvention showing the seal joint formed and the strap with the tensionin the supply portion thereof released;

FIG. 13 is a diagrammatic view of the operation of the machine of thisinvention showing the strap sheared;

FIG. 14 is a simplified schematic view of the electrical controlcircuit; and

FIG. 15 is a diagrammatic view of the pneumatic circuit of the presentmachine.

The strapping machine and head 1 embodying the invention herein used toproduce a bound package 11 of the type shown in FIG. 1 are usuallyprovided with two roller conveyors (not shown) for transporting anunbound package to the machine and a bound package away from themachine. The roller conveyors and the strapping machine and head I areeach suitably supported by appropriate support structure, the supportstructure having associated therewith a channel-shaped strap guide 9 forsuitably guiding a loop of strap 10 around a package 11 being strappedand ensuring that the leading end of the strap loop properly is fedunder the package 11 and up into proper location with the working pathof the strapping head 1.

With reference particularly to FIGS. 4 and 5, it is seen that thestrapping machine I is provided with a single large rectangular plate 12which is the main support frame for all components of the strappingmachine or head 1. The major operating portions of the head 1 consist ofthe strap feed, slack takeup and tensioning portion 13, a leading strapand gripping portion 14, the strap shear portion 15, the joint sealingor forming portion 16, the strap-gathering jaw portion 17, and the strapseal storing and feeding portion 18. In addition, there is a valvemanifold 19 which houses three air valves, there being an added airvalve for the shear portion 15 separate from the manifold 19, forcontrolling the air-powered portions of the machine powering theportions 13 to 18.

The strap feed, slack takeup and tensioning portion 13 is provided witha serrated rotary feed wheel or drum 20 which is secured to the end of ashaft 21. The shaft 21 is the drive shaft of an air motor 22 mounted onone side of the frame 12 and projecting through a circular hole 25 onthe other side of the frame 12. The rotary feed wheel 20 is positionedso that the teeth or serrations 26 about its periphery are parallel toan annular wall 27 on a drum or wheel 28 adjacent thereto. The wheel 28is considerably larger in diameter than the rotary feed wheel 20, thewheel 28 being mounted, particularly as shown in FIG. 9, on a bearing 30to the outer end of the shaft 29. The wheel 28 is free to rotate on thebearing 30' relative to the shaft 29 except during the tensioningoperation, as hereinafter explained. The shaft 29 is secured at itsinner end to a flange 31 which is secured to one end of a larger shaft32. The shaft 29 is mounted on the flange 31 with its center eccentriowith the center of the shaft 32. The shaft 32 is mounted betweenbearings 33 and 34 in a bearing housing 35 secured to the frame 12 bymeans of bolts 36.

The other end of the shaft 32 is secured to the lower end of an arm 37which extends radially outward from the shaft 32. The intermediateportion of the arm 37 is provided with an opening through which freelypasses a threaded shaft 38 mounted on a stud 39 which is secured to theframe 12. The other end of the threaded shaft 38 is provided with athreaded nut 38b which retains the arm 37 from falling off of the shaft38. Between the arm 37 and a portion near its end 38a, where there is athreaded nut 380, is a coil spring 30 reacting between the nut 38c andthe arm 37 to apply a rotating force on the shaft 32 tending to urge itin a counterclockwise direction shown by the arrow 41 in FIG. 4. Thefree end of the arm 37 is secured by a universal coupling 42 to one end43 of a rod 44. The other end 45 of the rod 44 is in line with theactuating arm 46 of a switch LS3, the rod 44 causing actuation of theswitch LS3 upon rotational movement of the shaft 32, as will hereinafterbe described.

Around the lower portion of the wheel 29 is a guide 47 for guiding thestrap 173 around the wheel 28 in the region from adjacent to the rotaryfeed wheel 20 to the front surface of the head 1.

Above the level of the strap feed slack takeup and. tensioning portion13 is the leading strap and gripping portion 14. With referenceparticularly to FIG. 7, the gripping portion 14 consists of two grippers56 and 57 pivoted respectively on two pins 58 and 59 mounted between twoside plates 60 and 61. The grippers 56 and 57 are provided withsharpened jaws 56a and 57a which are adapted to react against theleading end of the strap when it is positioned beneath the blade 55. Theblade 55 is provided with transverse grooves 55a (see FIG. which coactwith the smooth surfaces of jaws 56a and 57a so that the strap 173, whengripped, is deformed slightly into the transverse grooves for tightgripping thereof.

The blade 55 is secured to the frame 12 by the usual means and the blade55 has the functions of strap gripping and its leading edge 55b acts asa stationary shear blade, as hereinafter described. The blade 55 has anadditional function of strap guiding because its rear end 556 extendssubstantially to the region of the guide 47 where it guides the strap173 from the wheel 28 all the way into the joint sealing or formingportion 16.

The upper ends of the grippers 56 and 57 are pivoted on pins 65 to twotoggle links 66 which in turn are pivoted on a pin 67 to a yoke 68. Theyoke 68 is secured to a piston rod 69 of a piston contained in an aircylinder 70. In operation, the grippers 56 and 57 are positioned asshown in FIG. 7 and the piston rod 69 of the air cylinder 70 isretracted at that time. Upon extension of the piston rod 69 by admissionof air in the proper direction to the air cylinder 70, the pin 67 ismoved to cause the link 66 to pivot the grippers 56 and 57 and causetheir jaws 56a and 57a to grip a strap positioned beneath the blade 55.The cylinder 70 is secured by screws 71 to a pair of supports 72 whichare provided with a cover plate 73 and secured by means of screws 74 tothe sideplate 60. Above the blade 55 in this region is a fixed strapguide 75 which has a groove 76 formed in it to provide an opening largerthan the thickness of the strap 173 to be used where the supply strapcan be guided and moved freely even though the leading strap end 173a isgripped in a fixed position against the lower surface of the blade 55during tensioning.

Forward of the leading strap end gripping-portion 14 is first the strapshear portion 15 and then the joint sealing or joint forming portion 16.Both of these are shown particularly in FIG. 8 and are contained betweenthe two parallel sideplates 60 and 61 Both of the sideplates 60 and 61are held apart in parallel relationship by means of four spacers 77, 78,79 and 80. The sideplates 60 and 61 are assembled to the spacers bymeans of bolts 77a, 78a, 79a and 80a so as to provide a substantiallyclosed boxed-in structure. A sheet metal cover 81 surrounds a portion ofthe structure in order to conceal its mechanism. the housing beinghooked around the spacer 80 at one end and hooked onto the spacer 77 atthe other end and being easily removable for servicing.

The mechanism for joint scaling in the region 16 consists of a pluralityof six jaws 82 and 83, particularly shown in FIG. 8. There are, in thisparticular showing, four jaws 83 positioned two each opposite the twoothers and two jaws 82 positioned one opposite each other, also refer toFIGS. 4 and 5. The arrangement is such that the jaws 82 are alternatelysandwiched between the jaws 83, the jaws 82 and 83 being pivoted on pins85 to the sideplates 60 and 61. Each of the jaws 82 and 83 is providedwith recessed portions 86 which are adapted to engage the edges of aseal 142 and wrap it around overlapping strap ends 173 and 173::adjacent to it and cause a seal joint 88 to be formed by deforming theseal 142 and the strap ends with these recessed portions 86. The resultis a seal joint 88, as shown in FIG. 2, having tabs 89 which are theregions not contacted by thejaws 82 and 83 while the recessed portions86 of the sealer jaws 82, 83 engage beneath the remaining edge portions90. It should be emphasized at this point that the particular sealerjaws 82 and 83 and sealer mechanism generally used and shown herein arean example of a conventional type well known in the art and is notintended to be restricted to this particular form, it being merely shownby way of example.

In addition to the sealer jaws 82 and 83 being pivoted on the pins 85,they are also secured together by pins 91 so that they pivot integrally.The upper ends of the sealer jaws 83 are pivoted on pins 92 to twotoggle links 93 and 94. The toggle links 93 and 94 are in turn pivotedtogether on a pin 95 which is mounted between two slides 96 and anotherslide (not shown), see FIG. 8. The siide 96 is hereinafter referred toas the crosshead. Both the slide and the crosshead 96 are provided withanother pin 98 which is pivoted to two links 99, one link 99 beingadjacent to the slides and the other link 99 being adjacent to thecrosshead 96. These links 99 are in turn pivoted on a pin 100 to a gearsector 101. This gear sector 101 is pivoted on a pin 102 betweensideplates 60 and 61, the gear sector 101 having teeth 103 whichnormally engage teeth 104 on a rack 105 which is guided in twooppositely positioned grooves 106 formed in the sideplates 60 and 61.The rack 105 is mounted by means of two screws 107 to the piston rod 108of the air cylinder 109, as seen in FIG. 4, which is hereinafterreferred to as the sealer cylinder. In operation, the sealer parts areinitially retracted to their position in FIG. 8. As the piston rod 108is extended by admitting air under pressure in the proper direction tothe sealer cylinder 109, the rack 105 causes the gear sector 101 torotate on its pin 102 in a clockwise direction, as viewed in FIG. 8, andthis causes the sealer jaws 82 and 83 to pivot in such a manner that theoppositely positioned recess portions 86 are moved toward each other tocause a formation of a seal joint 88 when a seal 142 encircling twooverlapping strap ends is present in the sealing region. After jointformation, the rack is returned by retraction of the piston rod 108 toreturn all parts of the sealer mechanism to their original positions asshown in FIG. 8.

The strap shear portion 15 is particularly shown in FIGS. 6 and 8, thestrap shear portion 15 including a movable shear blade 100 having twospaced-apart elongated openings therein 111. The elongated openings 111providing room for the blade to move and not bind on the pins 85extending through the elongated openings 111. The blade 110 is alsoprovided with another elongated opening 112 which opening 1 12 receivestherethrough the pin 91, the elongated openings 111 and 112 providingfor sufficient freedom of movement for the blade 110 so that it may movefrom its stored position, as shown in FIG. 8, to its cutting position,as shown by the dotted lines in FIG. 6, without binding on the pins 85and 91. The movable blade 110 is pivoted at one end 113 thereof on pin78a, the blade 110 being provided with a hole for mounting of the bladeon the pin 78a. At the end of the blade 110 opposite to the pin 78a isprovided a hole 114, the hole 114 being provided to receive therethrougha connecting link to the actuating mechanism for the movable blade '110.There is further provided an air cylinder 300 having a spring-loadedpiston rod 301, which air cylinder 300 will hereinafter be referred toas the shear cylinder. The piston 301 is connected to the shear blade110 by means of an L-shaped linkage 303, the linkage 303 being connectedto the piston rod 301 by a nut 302 connecting the piston rod 301 to avertical plate 304, the vertical plate 304 is connected to a horizontalplate 305 which is supported by a diagonal support 306 to the verticalplate 304. A pin 307 connected to the horizontal plate 305 extendsthrough the hole 114 in the shear blade 110, thereby to connect theshear blade 1 with the piston 30] of the shear cylinder 300. Inoperation, when air is admitted under pressure to the shear cylinder300, the piston 301 is moved outwardly therefrom and causes, by means ofthe L-shaped linkage 303, the shear blade 110 to pivot around pin 78athereby to move the edge 115 of the shear blade 110 through a strappositioned in its path by reacting with the end 55b of the stationaryshear blade 55.

Above the joint sealing or forming portion 16 is a strap gathering jawportion 17, as particularly seen in FIGS. 4, 5 and 8, thestrap-gathering portion 17 being provided with an L- shaped link 117pivoted on pin 116, the link 117 having its other end pivoted on a pin118 to a first latch plate 119. The latch plate 119 is mounted to pivoton a hollow shaft 120 which is secured to the sideplate 61 by means of anut 121 threadably engaging its threaded outside surface. One end of theshaft 120 is a flanged end while its remaining portion is that which isthreaded. The flanged end retains the latch plate 119 on the shaft 120.Between the first latch plate 119 and the sideplate 61 is a second latchplate 122 which is also pivoted on the shaft 120 and has a protrudingportion provided with a pin 123 which projects into an opening 124extending through the sideplate 61. The pin 118 on the first latch plate119 also protrudes through an opening 125 extending through thesideplate 61. Both of the openings 124 and 125 are elongated to allowfor a limited length of travel of the pins 118 and 123 during pivotalmovement of both latch plates 119 and 122 on the shaft 120. A coilspring 126 surrounds the shaft 120 and has its opposite ends connectedaround the pins 118 and 123 in such a manner that the latch plates 119and 122 tend to be rotated in opposite directions by the force of thespring 126. There is also provided a latch bolt 127 of circular rodcross section which protrudes through the hollow shaft 120 and isprovided with a hook end 127a used ordinarily to engage one or both ofthe two notches 119a and 122a provided in the latch plates 119 and 122respectively. The other end 127b of the latch bolt 127 protrudes beyondthe opposite side of the sideplate 61 and is provided with an encirclingcompression spring 128 which is mounted to act against the first cotterpin 129 to urge the latch bolt 127 upwardly as viewed in FIG. 4. Thistendency of the spring 128 in this direction urges the end 127a of thelatch bolt 127 into the path of the notches 119a and 1220. The pin 123is suitably connected to a pair of gathering jaws 136 which constitutesthe strap-gathering jaw portion 17.

In operation, the retracted position of the jaws 136 is such that thejaws 136 are spread apart one from each other, this means that the pin123 is held toward the bottom of the slotted opening 124 with the latchplate 122 rotated to a position where its notch 122a is in alignmentwith the notch 119a on the latch plate 119 and the end 127a of the latchbolt 127 is engaged with both notches. When it is time in the operatingcycle of the machine for the strap-gathering jaws 136 to pivot intotheir operative position, the latch bolt 127 is moved downwardly, asviewed in FIG. 4. This allows the force of the spring 126 to pivot thegathering jaws 136 so that their free ends are brought toward each otherto intersect the ordinary path of the binder strap 173a during theoperation of the machine. Next, after the strap-gathering jaws 136 arein their strap-gathering position, the gear sector 101 is rotated by therack in order to move the link 117. This causes the latch plate 119 torotate clockwise and have its notch 119a moved to a position where it iscoincident with the notch 122a. When it reaches this position, the end127a of the latch bolt 127 again engages the notch 122a and this occursat the end of the joint sealing operation before strap shearing hasoccurred. Next, the rack 105 is retracted to rotate the gear sector 101in the opposite direction and pull the link 117 to rotate both of thelatch plates 119 and 122 together until pin 118 returns to the left endof the slot and the pin 123 returns to the lower end of the slot 124.The movement of the latch plate 122 at this time causes the togglelinkage associated with the gathering jaws 136 to spread their free endsapart from each other and out of the ordinary path of travel of thestrap 173. With all parts returned, they are ready for a repeat cycle ofoperation.

Beyond the strap-gathering jaw portion 17 is the strap seal storing andfeeding portion 18. As particularly seen in FIGS. 4 and 5, a sealstorage magazine 141 extends along the outside wall of the sideplate61a. Sideplate 61a is immediately adjacent to sidewall 61 and is securedto it by means of the same bolts 77a, 78a, 79a and 8011 which maintainthe sideplates 60 and 61 assembled together with their respectivespacers. Also the sideplate 61a is provided with an irregular cutoutsurface which provides room for the operating mechanism of the gatheringjaws 136. In addition, a cover plate 610 is positioned over sideplate61a and this conceals the gathering jaw mechanism 17. The bolts holdingsideplates 60, 61 and 61a together also hold the sideplate 61cassembled.

The seal magazine 141 houses a plurality of nested channelshaped seals142 which have a shape as shown particularly in FIG. 3. Each seal 142 isprovided with a back plate 142a bridged between two depending legs 142bwhich extend diagonally away from each other, the back plate 142a beingprovided with an aperture 142c therein. The seals 142 are stacked in theseal magazine 141 and remain in there stacked by means of aspring-loaded weight 143 and this manner of stacking and retaining sealsin a seal magazine is a relatively common expedient for a strappingmachine. As shown, the forward seal in the stack is positioned with itsdepending legs 142b resting on two plates 144 secured to the sealmagazine 141 by means of screws in the usual manner.

Pivoted on a pin 146 to the wall of the seal magazine 141 is a seal feedhinge 147. The seal feed hinge 147 has a free end provided with a sealfeed bar 148 pivoted to it on a pin 149 and this seal feed bar 148 isurged in a clockwise direction by means of a spring 150 coiled about thepin 149. Another spring 151 encircles the pin 146 and reacts between theseal magazine 141 and another pin 152 mounted through the seal feedhinge 147 in order to urge the seal feed hinge in a clockwise manner.The free end 153 of the seal feed bar is notched with a little shoulderto engage the edge of the endmost seal 142 when it is positioned withits depending legs 142b resting on a plate 144. Ordinarily, the sealfeed hinge 147 is retracted to the position shown in FIG. 5 with theseal feed bar engaging the forward seal 142, but the forward seal 142 isresisted from being displaced until the seal feed hinge 147 is pivotedon its pin 146 to drive the seal feed bar. As soon as the seal feedhinge 147 is released, endmost seal 142 is moved by the force of thespring 151 applied to the seal feed hinge 147 to cause the seal 142 tobe fed into a region between the sealing jaw 82 and 83 in preparationfor sealing. After a seal is fed, the pin 152 projecting laterally fromthe seal feed hinge 147 engages the extreme free end 127b of the latchbolt 127 to immediately cause the positioning of the strap-gatheringjaws 136, as previously described. The seal feed hinge 147 is returnedto its retracted position, see FIG. 4, by means of a roller 1S4 movingagainst the surface 155 on a projecting portion of the seal feed hinge147. The roller 154 is mounted on a pin 156 which is part of thecrosshead 96 actuated during movement of the sealing mechanism, and aspreviously described.

In order to clarify the relative sequential movement of the seal hinge147 with the sealer mechanism, the seal feed hinge 147 is first movedfrom the position shown in FIG. 5 to feed a seal 142 and it moves to aposition shown in FIG. 4 during this time. Then, the sealer mechanism isoperated to form a seal joint 88 and move the roller 154 against thesurface 155 of the seal feed hinge 147 in order to again retract itduring the joint forming period. There is a laterally extending plunger159 which is retracted through the frame 12 in order to release the sealfeed hinge 147 initially. Upon return movement of the seal feed hinge147 to its position shown in FIG. 5, an end surface of a projecting ear161 on the hinge 147 latches against the plunger 159 to retain the hinge147 in its retracted position.

Beyond the seal magazine 141 is a strap guide which extends for somedistance on both sides of which are mounted side guides 166 which arespring loaded and can be spread apart to allow for removal of the strap173 from between them. Likewise, there are two sideplates 167 and 168mounted on opposite sides of the straightening portion 148, as shown inFIG. 4. These are likewise spring loaded laterally against theirsupport. Specifically, all of the side guides 166, 167 and 168 areprovided with inwardly turned flanges, such as 16611 and 167a fortemporary strap retention. Also, the means for spring loading the guidestoward each other isby means of identical springs 169, each of whichconsists of a helical coil body secured at one end to a straight rodportion which passes essentially through the body portion and terminatesin a hooked end. By passing the hooked end through holes in each pair ofoppositely positioned side guides 166, 167 and 168 with the hooked endengaging the hole in the side guide positioned opposite to the side onwhich the body portion is located, the proper retention of the sideguides 166, 167 and 168 is achieved.

As shown in FIGS. 4 and 5, the seal feed hinge 147 is provided with aV-shaped link 170 having a central fiat portion 17012. The link 170 isconnected at its one end to the hinge 147 by means of a pin 171 and atits other end, the link 170 encircles the pin 156 of the crosshead 96 sothat one end of the link 170 moves with the hinge 147 while the otherend of the link 170 moves with the crosshead 96. The reason for this isto prevent actuation of the switch arm 172 of the switches LS2 and LSZaby means of the portion 17Gb of the link 1170 until both the seal feedhinge 147 and the sealer mechanism have been retracted. This isimportant to control certain operations of the machine as controlled bythe switches LS2 and LS2a. The essence of the importance of thisarrangement is that the seal feed hinge 147 must be retracted before thesealer mechanism is retracted, but both must be retracted beforeswitches LS2 and LS2a are operated and strap feed is initiated. Theswitches LS2 and LS2a are actuated only when the sealer jaws 82 and 83are open or in the retracted position, but if the jaws 82 and 83 are inthe retracted position, then movement of the seal feed hinge 147 mayalso actuate the switches LS2 and LS2a, all as will hereinafter beexplained.

As shown in FIG. 5, there is a spring-loaded plunger 178 which is urgedto the right as viewed in FIG. 5. The purpose of this spring-loadedplunger is to deflect the leading end 173a of the strap 173 when it isinitially fed past the gathering jaw region 17 to deflect the strap endaway from the seals 142 stacked in the seal magazine 141 to preventcontact of the strap end 1730 with the seals 142 and thereby arreststrap feed. The tendency for this to happen would be increased in caseof a strap 173 with an end 173a curved or otherwise deformed in thedirection toward the seal magazine 141.

Before describing the electrical and pneumatic circuits, the followingsummary of the mechanical operation of the strapping apparatus ispresented, particular reference being made to FIG. 5 and the sequentialfigures 10 to 13. Initially, the strapping head 1 is presented with apackage 11 and a length of strap 173 is fed from a suitable supplysource through a guide 174 in the direction of the arrow (FIG. 10) inorder to feed the strap 173 between the rotary feed wheel 20 and thewheel 28. Then, the rotary feed wheel 20 is rotated by its air motor 22to feed a length of strap around the wheel 28, past the leadingstrapping end gripping portion 14, the strap shear portion 15, the jointsealing or forming portion 16, the strap-gathering jaw portion 17, thestrap seal storing and feeding portion 18, and into a region beyond theside guides 166. This leaves a free end of the strap 173a protrudingabove the level of the strapping head 1. At this time, the seal feedhinge 147 is released by retracting the plunger 159 to feed a seal 142into a position between the sealer jaws 82 and 83. The strap lengthpositioned in the strapping machine 1 acts as a guide along which theseal 142 is fed and it also acts as a retaining means to prevent theseal 142 from dropping out of the head 1 after it is fed. This leadingstrap end 173a is grasped by the operator and manually encircledforward, around and beneath the package 11 and guided by the bottom ofthe guide channel 9 provided in front of the machine. This guide channel9 guides the strap 173 up below the blade 55 between the side guides 167and 168 on the strap-straightening portion 48, past all of the mechanismleading to the strapgathen'ng jaw portion 17 and is finally deflected bythe gathering jaws 136 where the leading strap end 173a is arrested inits forward movement. The front surface of each gathering jaw 136 isprovided with a sloped surface 177 which provides a deflection for thestrap end 1730 and terminates its forward movements. At this time, thepackage 11 rests on the associated conveyor links with the strap loop 10loosely surrounding it, all as illustrated in FIG. 10.

The leading strap end gripping jaws 56a and 57a are then pivoted to gripthe leading strap end 173 against the bottom surface of the blade 55 andsimultaneously the rotary feed wheel 20 is rotated in a reversedirection to cause reverse movement of the strap 173 in order towithdraw a slack from the strap loop 10 loosely surrounding the package11. At the end of the strap slack takeup period, the rotary feed wheel20 causes the strap 173 to be tensioned tightly onto the package 11.After tensioning is complete, a signal from the tensioning means causesactuation of the piston of the sealer cylinder 109 to cause the sealingportion 16 to form a seal joint of the type shown in FIG. 2 between theoverlapping ends of the strap 173, all as illustrated in FIG. 11. At theend of the joint-forming stroke, a signal from the joint-forming meanscauses the tensioning means to release the tension in the supply portionof the strap 173, as seen in FIG. 12, and thereafter aetuates theshearing means to sever the supply end from the strap loop, as seen inFIG. 13. Thereafter, the leading strap end gripping portion 14 isactuated in the direction to allow removal of the strap loop with thepackage 11 as the package 11 is moved down the rollerconveyorssupporting it. Releasing the tension before severing isextremely important when using polypropylene strap because severing thepolypropylene strap when it: is under tension causes frayed ends whilereleas ing the tension in the strap provides a cleanly severed free endof the strap adjacent to the seal joint 88 and provides a cleanlysevered leading end 173a of the strap 173 on the supply portion thereof.The leading strap end gripping portion 14 is released when the tensionin the strap 173 is released. After a new length of strap has been fedinto the machine far enough to pass between the guide blades 166 andbeyond them, the machine 1 is ready for a new operating cycle.

Having referred to the general mechanical operation of the machine 1,the electrical circuitry will be described with reference to FIG. 14. Asseen, there are two electric wires 179 and 180 which are connected toopposite sides of an electric input, the wire 179 being connected tocontact 1810 of a normally open master switch 181. A wire 191 isconnected to the other contact [81b of the normally open master switch181 and leads to a contact 182a of a cycle switch 182. A wire 191a isconnected to the other contact 182b of the cycle switch 182. The wire191 is also connected to contact LS2b of normally open switch LS2a. Awire 191b connects the other contact LSZc of switch LS2a to a contact183c of a control relay switch 18317, and the other contact 183d of thecontrol relay switch 183b is connected to wire 191a, which wire 191a isalso connected to a control relay switch 183 including a control relaysolenoid 183 a. It is noted that the cycle switch 182 is in parallelwith the switch LS2a and the control relay switch 183b.

In parallel with the control relay switch 183 is a normally open switchLS3 having contacts LS3a, one of the contacts LS3a being connected by awire 191a to a time control relay 184 having a solenoid 184a. Also inparallel to the control relay 183 and the switch LS3 is a normally opentime delay relay switch 184b having contacts 184d, one of which contacts184a is connected by a wire 191d to the sealer valve 190 and a solenoid190a therefor. Also in parallel to the sealer valve 190, the time delayrelay 184 and the control relay 183 is a normally open switch LS1 havingcontacts LSlb, one of which is connected by wire l9le to the tension andgripping valve 189 having a solenoid 189a therefor. A normally closedswitch LSla having contacts LSlc is connected in series by wire 191f tothe other contact LSlb of normally open switch LS1. Connected in seriesto the normally closed switch LSla is a normally closed time delayswitch 184c having contacts 184e. A wire 191g connects the other side ofthe normally closed time delay relay 184C to the shear valve 320 and asolenoid 320a therefor. It is noted that the shear valve 320 isconnected to the opposite side of the normally closed time delay switch1840 than the normally closed switch LSla. There is also provided anormally open manual sealer switch 203 connected at one end thereof towire 191 and at the other end thereof by wire 191e to the sealer valve190. A normally open manual shear valve switch 204 is connected at oneend to wire 191 and at the other end to the shear valve 320 by wire191g. Also leading from wire 191 is a branch circuit containing anormaily open relay switch 185b and a seal feed plunger solenoid 188.Also connected to wire 191 is a normally open manual strap feed switch187 leading to a juncture 192 in parallel with a normally closed switchLS2 leading to the same juncture 192. Beyond the juncture 192 are twoparallel circuits, the first of which contains solenoid 185a of a timedelay relay 185 and the second of which contains solenoid 186a of thestrap feed valve 186. It should be noted that the relay switches 184band 184c are actuated by energization and deenergization of solenoid184a of time delay relay 184, relay switch l83b is actuated by relaysolenoid 183a and relay switch 18512 is operated by relay solenoid 185a.

ln FIG. which shows the pneumatic circuit, there are shown the threecontrol valves, 190, 186 and 189, which valves are physically positionedtogether in the manifold 19, and a fourth control valve 320 apart fromthe manifold 19. A source of high-pressure fluid 193 is connected by aconduit 194 to the valve 190. The valve 190 is connected to the sealercylinder 109 by means of a conduit 200, which conduit 200 also leads tothe shear valve 320, the shear valve 320 being connected to the shearcylinder 300 by a conduit 321. The valve 190 is also connected to anexhaust conduit 195 and another conduit 196. Both conduits 195 and 196lead into valve 186 and this valve has two conduits 197 and 198 leadingfrom it to a third valve 189. From valve 189 is an exhaust conduit 199leading to the atmosphere. Both the conduits 195 and 197 are connectedto a common exhaust leading to exhaust conduit 199. Both conduits 196and 198 are connected to the their respective piston rods and 301 arealso of the springreturn type.

To summarize the entire operation of the machine, with respect to theelectrical and pneumatic circuits, initially the machine is put intooperation by inserting the leading strap end 173a of a supply of strapbetween the rotary feed wheel 20 and the drive wheel 28. The supply ofstrap is ordinarily a coil of strap positioned in a convenient fixedplace relative to the installation where the strapping head or machine 1is located. As shown in FIG. 4, the strap can be inserted through aguide 174 which leads into the region between the rotary feed wheel 20and the wheel 28. Also the operator must fill the seal magazine 141 witha plurality of stacked seals 142 by first removing the spring-loadedweight 143 and then replacing it after the seals 142 have been placed inthe magazine 141. hitially the seal feed hinge 147 is latched to aposition indicated in FIG. 5, the manual seal switch 203 is open, themanual shear switch 204 is open, the manual strap feed switch 187 isopen, the master switch 181 is open, the cycle switch 182 is open, theswitch LS2a is open, the switch 183b is open, the switch LS3 is open,the switch 184b is open, the switch 184a is closed, the switch LS 1a isclosed, the switch LS1 is open, the switch 18517 is open and the switchLS2 is closed. At this time, the master switch 181 is closed. Thisenergizes the strap feed solenoid 186a and the time delay relay solenoid185a through the contact of closed switch LS2. Energizing the strap feedsolenoid 186a actuates the solenoid valve 186 to cause air pressure fromthe high-pressure source 193 to be fed through conduits 194 and 196 toconduit 201. The air pressure in conduit 201 feeds the air motor 22. Thepiston rod 69 of the leading strap end gripping cylinder 70 remainsretracted due to the spring loading thereof so that the strap endgripping members 56 and 57 are retracted out of the path of the strap173. Feeding of the air pressure to the air motor 22 causes it to rotatethe rotary feed wheel 20 in a direction to feed strap 173 into themachine 1 past the operating portions at the front face of the machine.The energized time delay relay solenoid 185a permits the strap 173 to befed for approximately 1 second for the particular embodiment shownherein. This is accomplished by having the solenoid delay the closing ofits relay switch l85b for one second. After one second, the relay switch18512 closes to energize the seal feed plunger solenoid 188. This causesthe plunger 159 to retract and allow the seal feed hinge 147 to pivotfrom a position as shown in FIG. 5 to a position as shown in FIG. 4.During this time a seal 142 is fed from the seal stack in the sealmagazine 141 over the strap 173 previously fed into the machine 1 untilthe seal 142 is positioned within the sealing region of the sealer jaws82 and 83. The seal 142 is arrested in its forward movement as itcontacts the sideplate 60. The pivoting of the seal feed hinge 147immediately causes the arm 171 to move and cause switch LS2 to open andswitch LS2a to close. The closing of the switch LS2a merely prepares theholding circuit including the control relay 183 for future use when thecycle switch 182 is closed. The opening of the switch LS2 immediatelydeenergizes the solenoid 185a of the time delay relay 185 and also thesole noid 186a of the strap feed valve 186 to arrest strap feed. As thetime delay relay solenoid 185a is deenergized, its relay switch l85bagain opens to free the plunger 159 of the magnetic pull of the sealfeed plunger solenoid 188. The plunger 159 is spring loaded outwardlytoward the flange 161 on the seal feed hinge 147 against which it restsat this time.

As the plunger 159 is retracted initially, it strikes the arm ofswitches LS1 and LSla to close the switch LS1 and to open the switchLSla. Opening of the switch LSla prevents the shear valve 320 from beingactuated when the time delay relay 284 is actuated. Closing the switchLS1 merely prepares the strap tensioning and gripping circuit for itslater operation. Also, as the seal feed hinge 147 pivots downwardly, thepin 152 on it strikes the latch bolt 127 to release the latch plate 122and cause the gathering jaws 136 to assume a position where their freeends are in the path of the strap 173.

The one second delay period for the strap feed is calculated to feed outonly enough strap 173 that it projects slightly above the head 1, thisnot being intended to be enough length of strap for encircling apackage. Therefore, the manual strap feed switch 187 is closed to feedout additional strap 173 by energizing the strap feed valve solenoid186a. The manual strap feed switch 187 is held closed for as long aperiod as required to feed out the length of strap 173 needed. Eventhough the electrical circuit permits the time delay relay solenoid 185ato again be energized to this time, if it is energized long enough toallow its relay switch 18511 to close and energize the seal feed plungersolenoid 188, there is no physical effect at this time because theplunger is being held retracted by the flange 161 of the seal feed hinge147.

With sufficient strap 173 drawn off, the operator manipulates it over,around and beneath the package 11 to be strapped and forces the leadingstrap end 173a into the guide 9 below the top level of the associatedroller conveyors where it is guided into the working regions at thefront of the strapping head 1. The strap 173 is guided up to the strapgathering jaws 136 where its upward movement is halted.

It should be emphasized that the feed of a seal 142 is deliberatelydelayed until after the strap 173 is fed into the machine 1 during theone second time delay. The reason for this is to feed the strap 173 intoposition with a minimum of possibility of the leading strap end 173acatching on anything in its path. With both the seal feed mechanism andthe seal 142 to be fed out of the way at this time, there is asubstantially clear path for the strap 173 to follow without too muchrisk of snagging. The machine was deliberately designed with thissequencing of having the seal feed follow the strap feed to provideanother advantage which is that the strap 173 itself acts as a guideduring the time the seal 142 is fed into the sealer portion and thestrap 173 also acts as a support for the seal 142 to prevent the seal142 from falling out of the machine 1. On prior devices, where the strap173 is not used to support the seal 142, separate holding means isrequired for the seal 142 during strap feed.

Next, the cycle switch 182 is closed and this energizes the controlrelay solenoid 183a and the solenoid 189a of the tension and gripsolenoid valve 189. Energizing the control relay solenoid 183a closesits relay switch 183!) which acts as a holding contact or circuit uponrelease of the cycle switch 182 to its open position. When the tensionin grip valve 189 is actuated at this time, it causes high pressure airto pass through the conduit 202 and into the opposite side of both theair motor 22 and the leading strap end gripping cylinder 70.Immediately, the piston rod 69 extends to close the gripping jaws 56aand 57a to grip the leading strap end 173a against the undersurface ofthe blade 55. Simultaneously therewith, the air motor 22 rotates in thedirection opposite to its rotation during strap feed and this causeswithdrawal of the strap 173 around the wheel 28 in a clockwise directionas viewed in FIG. 5 and also FIG. 11. Strap withdrawal continues untilall of the slack is taken up in the strap loop encircling the package 11and continues until a certain degree of tension is reached. When thiscertain degree of tension is reached, there is a deflection of the wheelshaft 29 and its related parts and the shaft 21 of the rotary feed wheelin combination with a certain movement resulting from gripping contactof the serrations 26 on the rotary feed wheel 20 with the strap. Thismovement of the strap feed parts by deflection provides a certainangular movement of the arm 37 and this in turn causes movement of therod 44 to allow actuation of the switch LS3.

Actuation of the switch LS3 at this time closes its contacts LS3a toenergize the relay solenoid 1840 of time delay relay 184. Energizing thetime delay relay 184 closes relay switch 184k and opens relay switch184a after a short time delay. Opening of the relay switch 184C has noeffect because the switch LSla is also open at this time, but preventsactuation of the shear valve 320 until after the tensioning mechanismhas been released. Closing of the relay switch 1841: causes energizationof the solenoid 190a of the sealer valve 190. This causes high pressureto flow through conduit 200 and into the sealer cylinder 109 to causeits piston rod 108 to extend and actuate the sealer jaws 82 and 83 toform a seal joint 88 of the type shown in FIG. 2. The time delayprovided by relay 184 ensures that full tension is reached in the strap173 before the sealer mechanism is operated and provides enough time toensure that full compression of a compressible object being strappedoccurs. Also, when a plurality of heads 1 are being used, the time delayis set long enough to guarantee that full tension is reached by allheads before any one of them operates the seal to form a joint.

While the sealer jaws 82 and 83 are closing around the strap 173 to forma seal joint 88, the seal feed hinge 147 returns to its latched positionand allows the seal feed solenoid plunger 188 to assume its deenergizedposition which then causes actuation of the LS1 switches. At this time,the LS1 switch opens and the LSla switch closes, but since switch 184ais now open the shear valve 320 is not actuated. When the switch LS1opens, the tension and grip solenoid 189a deenergizes and as the tensionin the supply portion of the strap 173 backs off, the LS3 switch opensup due to a resumption of the original spatial relationship betweenwheels 20 and 28 and hence the return of rod 44 and arm 37 to theiroriginal position. When the LS3 switch opens, the time delay relay 184deenergizes and the time delay switch 18411 opens and the time delayswitch 184c closes. When the time delay switch 18 1b opens, the sealersolenoid 190a is deenergized and when the time delay switch 1840 closes,the shear solenoid 320a and valve 320 associated therewith are actuated.The valve 190 has a pneumatic time delay on deenergization whichprovides for a given time interval between the deenergization of thesolenoid 190a and the release of high-pressure air in the conduit 200 toprovide time for the shear mechanism to actuate. When highpressure airwas fed to the cylinder 109 through the conduit 200, it also was fed tothe shear valve 320 and actuation of the shear valve 320 by energizationof the shear valve solenoid 320a at this time admits high-pressure airthrough conduit 321 into the shear cylinder 300 thereby moving thepiston and piston rod 301 forward to cause the shear blade 110 andparticularly the edge thereof into shearing relationship with thestationary shear blade 55 thereby to sever the strap 173 after thetension therein has been released to provide a cleanly severed free endof the strap 173 adjacent to the seal joint 88 and to provide a cleanlysevered leading end 173a on the supply portion of the strap 173.

When the sealer jaws 82 and 83 open, and the seal feed hinge 147 is inits latched position, the switches LS2 and LS2a are again actuated sothat the switch LS2 closes and the switch LSZa opens. When the switchLS2a opens, this deenergizes the shear solenoid 320a and also theholding circuit including the relay switch 183!) and the solenoid 183a.During the return movement of the sealer parts, the crosshead 96 isretracted so that the V-shaped arm is also fully retracted to where theportion 170b of this am has contacted the switch arm 172 to activate theswitches LS2 and LS2a as hereinbefore disclosed. Closing of the switchLS2 and the opening of the switch LSZa coupled with the deenergizationof the shear solenoid 320a, returns all the operating parts to theirinitial position and initiates the l-second time period of strap feedcaused by the time delay relay and leaves the end of the operating cyclewith a portion of strap fed into the machine and extending above thelevel of the strapping head 1. The machine is then in readiness for thenext cycle of operation which is initiated by again closing the manualfeed strap switch 187 to feed out a sufficient length of strap toencircle the next object or package to be strapped.

Ordinarily, at the time when the air is released from the conduit 202,the leading strap end gripping piston rod 69 is urged to a retractedposition by means of an internal spring. Note that the strapped packagecannot be removed from the machine before this occurs because thegripping jaws 56a and 57a are holding the strap loop up against thefront face of the strapping head 1.

Although only a single embodiment of the invention has been shown anddescribed, it should be understood that the in vention can be made inmany different ways without departing from the true scope of theinvention as defined by the appended claims.

What is claimed is:

l. A strapping machine for applying a plastic strap around an object,said strapping machine comprising strap-gripping means for holding theleading end of the strap encircled about the object and overlapping asupply portion of the strap, sealfeeding means for feeding a seal to besealed around the overlapping portion of said strap after the strap isin the overlapping position thereof, tensioning means for tensioning theloop of strap by withdrawing the supply portion of the strap relative tothe leading end of the strap, sealing means for securing together theleading end of the strap and the adjacent supply portion of the strap toprovide a seal joint therebetween by applying the seal around theoverlapped portion of the strapping, control means for said tensioningmeans responsive to completion of the operation of said sealing meansfor releasing the tension in the supply portion of the strap, and strapsevering mechanism for severing the supply portion of the strap adjacentto the seal joint after the tension in the strap has been released andafter said sealing means has been released from applying the seal aroundthe overlapped portion of the strapping, whereby to provide a cleanlysevered free end of the strap adjacent to the seal joint and to providea cleanly severed leading end of the strap on the supply portionthereof.

2. A strapping machine for applying a plastic strap around an object,said strapping machine comprising strap-gripping means for holding theleading end of the strap encircled about the object and overlapping asupply portion of the strap, sealfeeding means for feeding a seal to besealed around the overlapping portion of said strap after the strap isin the overlapping position thereof, tensioning means for tensioning theloop of strap by withdrawing the supply portion of the strap relative tothe leading end of the strap, sealing means for securing together theleading end of the strap and the adjacent supply portion of the strap toprovide a seal joint therebetween by applying the seal around theoverlapped portion of the strapping, control means for said tensioningmeans responsive to completion of the operation of said sealing meansfor releasing the tension in the supply portion of the strap,strap-severing mechanism for severing the supply portion of the strapadjacent to the seal joint, a fluid motor for operating saidstrap-severing mechanism to sever the supply portion of the strap, andcontrol mechanism for said fluid motor responsive to release of tensionin the supply portion of the strap for operating said motor and aftersaid sealing means has been released from applying the seal around theoverlapped portion of the strapping, whereby to provide a cleanlysevered free end of the strap adjacent to the seal joint and to providea cleanly severed leading end of the strap on the supply portionthereof.

3. The strapping machine set forth in 2, wherein said fluid motor foroperating said strap-severing mechanism is an air motor.

4. The strapping machine set forth in 2, wherein said fluid motor foroperating said strap-severing mechanism is a reciprocating air motor.

5. A strapping machine for applying a plastic strap around an object,said strapping machine comprising strap-gripping means for holding theleading end of the strap encircled about the object and overlapping asupply portion of the strap, sealfeeding means for feeding a seal to besealed around the overlapping portion of said strap after the strap isin the overlapping position thereof, first and second cooperating drivedrums positioned to have the supply portion of the strap passingtherebetween, motor means for driving one of said first and second drivedrums to supply strap to form a loop encircled about the object and fortensioning the loop of strap by withdrawing the supply portion of thestrap-relative to the leading end of the strap, sealing means forsecuring together the leading end of the strap and the adjacent supplyportion of the strap to provide a seal joint therebetween by applyingthe seal around the overlapped portion of the strapping, control meansfor said motor means responsive to completion of the operation of saidsealing means for releasing the tension in the supply portion of thestrap, and strap-severing mechanism for severing the supply portion ofthe strap adjacent to the seal joint after the tension in the strap hasbeen released and after said sealing means has been released fromapplying the seal around the overlapped portion of the strapping,whereby to provide a cleanly severed free end of the strap adjacent tothe seal joint and to provide a cleanly severed leading end of the strapon the supply portion thereof.

6. The strapping machine set forth in 5, wherein said driven drum hasserrations thereabout for driving the plasticstrap.

7. The strapping machine set forth in 5, wherein one of said drums ismounted on an eccentric shaft, said eccentric shaft being so alignedwith respect to the other one of said drums that tension in the strapurges rotation of said eccentric shaft and urges the drum mounted onsaid shaft bodily toward the other one of said drums to increase thegrip on the strap passed therebetween as strap tension increases,

8. The strapping machine set forth in 5, wherein one of said drums ismounted on an eccentric shaft, said eccentric shaft being so alignedwith respect to the other one of said drums that tension in the strapurges rotation of said eccentric shaft and urges the drum mounted onsaid shaft bodily toward the other one of said drums to increase thegrip on the strap passed therebetween as strap tension increases, andcontrol means for said sealing means responsive to rotation of saideccentric shaft for activating said sealing means.

- 9. The strapping machine set forth in 5, wherein one of said drums ismounted on an eccentric shaft, said eccentric shaft being so alignedwith respect to the other one of said drums that tension in the strapurges rotation of said eccentric shaft and urges the drum mounted onsaid shaft bodily toward the other one of said drums to increase thegrip on the strap passed therebetween as strap tension increases, saideccentric shaft being provided with an ann positioned to move through anangular path as the eccentric shaft is rotated on its axis in responseto bodily movement of said drum toward one another, rotation of saideccentric shaft causing said arm to actuate said sealing means.

10. A strapping machine for applying a plastic strap around an object,said strapping machine comprising strap-gripping means for holding theleading end of the strap encircled about the object and overlapping asupply portion of the strap, sealfeeding means for feeding a seal to besealed around the overlapping portion of said strap after the strap isin the overlapping position thereof, tensioning means for tensioning theloop of strap by withdrawing the supply portion of the strap relative tothe leading end of the strap, sealing means for securing together theleading end of the strap and the adjacent supply portion of the strap toprovide a seal joint therebetween by applying the seal around theoverlapped portion of the strapping, control mechanism for said sealingmeans responsive to a predetermined tension in the loop of strap foractivating said sealing means, control means for said tensioning meansresponsive to completion of the operation of said sealing means forreleasing the tension in the supply portion of the strap, and saidstrap-severing mechanism for severing the supply portion of the strapadjacent to the seal joint after the tension in the strap has beenreleased and after said sealing means has been released from applyingthe seal around the overlapped portion of the strapping, whereby toprovide a cleanly severed free end of the strap adjacent to the sealjoint and to provide a cleanly severed leading end of the strap on thesupply portion thereof.

11. The strapping machine set forth in 10, wherein the predeterminedtension is the maximum tension attained in the loop of strap by saidtensioning means.

12. The strapping machine set forth in 10, wherein said controlmechanism for said sealing means is provided with a time delay means fordelaying the immediate operation of said sealing means when thepredetermined tension has been reached.

13. The strapping machine set forth in 10, and further including controlmechanism for preventing the feeding of the supply portion of the strapduring the formation of the seal oint. 7

14. A strapping machine for applying a plastic strap around an object,said strapping machine comprising mechanism for guiding the leading endof a length of strap leading from a strap supply and looped around anobject and overlapping a supply portion of the strap, seal-feeding meansfor feeding a seal to be sealed around the overlapping portion of saidstrap after the strap is in the overlapping position thereof, tensioningmeans for tensioning the loop of strap by withdrawing the supply portionof the strap relative to the leading end of the strap, a blade overwhich the strap passes, jaws for gripping the leading end of the strapagainst the blade, said blade hav ing a portion with transverse groovesformed therein and said jaws forcing the material of the strap into thegrooves to hold the strap taut during the operation of said tensioningmeans, sealing means for securing together the leading end of the strapand the adjacent supply portion of the strap to provide a seal jointtherebetween by applying the seal around the overlapped portion of thestrapping, control means for said tensioning means responsive tocompletion of the operation of said sealing means for releasing thetension in the supply portion of the strap, and a movable strap shearmeans for coacting against another portion of said blade for severingthe supply portion of the strap adjacent to the seal joint after thetension in the strap has been released and after said sealing means hasbeen released from applying the seal around the overlapped portion ofthe strapping, whereby to provide a cleanly severed free end of thestrap adjacent to the seal joint and to provide a cleanly severedleading end of the strap on the supply portion thereof.

15. The strapping machine set forth in 14, wherein said movable strapshear means is activated by a fluid motor.

16. The strapping machine set forth in 14, wherein said movable strapshear means is activated by an air motor.

17. The strapping machine set forth in 14, and further comprisingcontrol mechanism to prevent feeding of strap from the strap supplyduring strap severing.

18. A strapping machine for applying a plastic strap around an object,said strapping machine comprising strap-gripping means for holding theleading end of the strap encircled about the object and overlapping asupply portion of the strap, sealfeeding means for feeding a seal to besealed around the overlapping portion of said strap after the strap isin the overlapping position thereof, tensioning means for tensioning theloop of strap by withdrawing the supply portion of the strap relative tothe leading end of the strap, a first fluid motor for operating saidstrap-gripping means and said tensioning means for causing simultaneousactuation of said tensioning means and said strap-gripping means,sealing means for securing together the leading end of the strap and theadjacent supply portion of the strap to provide a seal jointtherebetween by applying the seal around the overlapped portion of thestrapping, a second fluid motor for operating said sealing means,control mechanism for said second fluid motor responsive to apredetermined tension in the supply portion of the strap for activatingsaid second fluid motor, control means for said first fluid motorresponsive to completion of the operation of said sealing means forreleasing the tension in the supply portion of the strap, strap-severingmechanism for severing the supply portion of the strap adjacent to theseal joint, a third fluid motor for operating said strap-severingmechanism to sever the supply portion of the strap, and controlmechanism for said third fluid motor responsive to release of tension inthe supply portion of the strap and afier said sealing means has beenreleased from applying the seal around the overlapped portion of thestrapping, for operating said third fluid motor, whereby to provide a ceanly severed ree end of the strap adjacent to the seal joint and toprovide a cleanly severed leading end of the strap on the supply portionthereof.

19. The strapping machine set forth in 18, wherein said first fluidmotor is an air motor.

20. The strapping machine set forth in 18, wherein said second fluidmotor is an air motor.

21. The strapping machine set forth in 18, wherein said third fluidmotor is an air motor.

22. The strapping machine set forth in 18, wherein said first and thirdfluid motors are reciprocating air motors.

. 23. A strapping machine for applying a plastic strap around an object,said strapping machine comprising mechanism for guiding the leading endof a supply portion of a length of strap leading from a strap supply andlooped around an object, sealfeeding means for feeding a seal to besealed around the overlapping portion of said strap after the strap isin the overlapping position thereof, first and second cooperating drivedrums positioned to have the supply portion of the strap passingtherebetween, a blade over which the strap passes, jaws for gripping theleading edge of the strap against the blade, said blade having a portionwith transverse grooves formed therein and said jaws forcing thematerial of the strap into the grooves to hole the strap taut when thejaws are in the strap-gripping position thereof, a first fluid motor forsimultaneously tensioning the loop of strap by withdrawing the supplyportion of the strap relative to the leading end of the strap andactuating said gripping jaws, sealing means for securing together theleading end of the strap and the adjacent supply portion of the strap toprovide a sealed joint therebetween by applying the seal around theoverlapped portion of the strapping, a second fluid motor for operatingsaid sealing means, control mechanism for said second fluid motorresponsive to said first and second cooperating drive drums at apredetermined tension in the supply portion of the strap for activatingsaid second fluid motor, control means for said first fluid motorresponsive to completion of the operation of said sealing means forreleasing the tension in the supply portion of the strap, a movablestrap shear means for coacting against another portion of said blade forsevering the supply portion of the strap adjacent to the sealed joint, athird fluid motor for operating said strap shear means to sever thesupply portion of the strap, and control mechanism for said third fluidmotor responsive to release of tension in the supply portion of thestrap and after said sealing means has been released from applying theseal around the overlapped portion of the strapping for operating saidthird fluid motor, whereby to provide a cleanly severed free end of thestrap adjacent to the sealed joint and to provide a cleanly severedleading end of the strap on the supply portion thereof.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTEQN Patent $636,861 %ny ;,.,11. Z2;ji

Invento (s)Frank-C. Weller It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

Item +5 should read --Jan. 25, l972-.

Signed and sealed this 5th day of September 1972 (SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissionerof Patents USCOMM-DC 60376-P59 U 5 GOVERNMEN] PRINTING OFFICE: 1969 O3E6 33A

1. A strapping machine for applying a plastic strap around an object,said strapping machine comprising strap-gripping means for holding theleading end of the strap encircled about the object and overlapping asupply portion of the strap, sealfeeding means for feeding a seal to besealed around the overlapping portion of said strap after the strap isin the overlapping position thereof, tensioning means for tensioning theloop of strap by withdrawing the supply portion of the strap relative tothe leading end of the strap, sealing means for securing together theleading end of the strap and the adjacent supply portion of the strap toprovide a seal joint therebetween by applying the seal around theoverlapped portion of the strapping, control means for said tensioningmeans responsive to completion of the operation of said sealing meansfor releasing the tension in the supply portion of the strap, and strapsevering mechanism for severing the supply portion of the strap adjacentto the seal joint after the tension in the strap has been released andafter said sealing means has been released from applying the seal aroundthe overlapped portion of the strapping, whereby to provide a cleanlysevered free end of the strap adjacent to the seal joint and to providea cleanly severed leading end of the strap on the supply portionthereof.
 2. A strapping machine for applying a plastic strap around anobject, said strapping machine comprising strap-gripping means forholding the leading end of the strap encircled about the object andoVerlapping a supply portion of the strap, seal-feeding means forfeeding a seal to be sealed around the overlapping portion of said strapafter the strap is in the overlapping position thereof, tensioning meansfor tensioning the loop of strap by withdrawing the supply portion ofthe strap relative to the leading end of the strap, sealing means forsecuring together the leading end of the strap and the adjacent supplyportion of the strap to provide a seal joint therebetween by applyingthe seal around the overlapped portion of the strapping, control meansfor said tensioning means responsive to completion of the operation ofsaid sealing means for releasing the tension in the supply portion ofthe strap, strap-severing mechanism for severing the supply portion ofthe strap adjacent to the seal joint, a fluid motor for operating saidstrap-severing mechanism to sever the supply portion of the strap, andcontrol mechanism for said fluid motor responsive to release of tensionin the supply portion of the strap for operating said motor and aftersaid sealing means has been released from applying the seal around theoverlapped portion of the strapping, whereby to provide a cleanlysevered free end of the strap adjacent to the seal joint and to providea cleanly severed leading end of the strap on the supply portionthereof.
 3. The strapping machine set forth in 2, wherein said fluidmotor for operating said strap-severing mechanism is an air motor. 4.The strapping machine set forth in 2, wherein said fluid motor foroperating said strap-severing mechanism is a reciprocating air motor. 5.A strapping machine for applying a plastic strap around an object, saidstrapping machine comprising strap-gripping means for holding theleading end of the strap encircled about the object and overlapping asupply portion of the strap, seal-feeding means for feeding a seal to besealed around the overlapping portion of said strap after the strap isin the overlapping position thereof, first and second cooperating drivedrums positioned to have the supply portion of the strap passingtherebetween, motor means for driving one of said first and second drivedrums to supply strap to form a loop encircled about the object and fortensioning the loop of strap by withdrawing the supply portion of thestrap relative to the leading end of the strap, sealing means forsecuring together the leading end of the strap and the adjacent supplyportion of the strap to provide a seal joint therebetween by applyingthe seal around the overlapped portion of the strapping, control meansfor said motor means responsive to completion of the operation of saidsealing means for releasing the tension in the supply portion of thestrap, and strap-severing mechanism for severing the supply portion ofthe strap adjacent to the seal joint after the tension in the strap hasbeen released and after said sealing means has been released fromapplying the seal around the overlapped portion of the strapping,whereby to provide a cleanly severed free end of the strap adjacent tothe seal joint and to provide a cleanly severed leading end of the strapon the supply portion thereof.
 6. The strapping machine set forth in 5,wherein said driven drum has serrations thereabout for driving theplastic strap.
 7. The strapping machine set forth in 5, wherein one ofsaid drums is mounted on an eccentric shaft, said eccentric shaft beingso aligned with respect to the other one of said drums that tension inthe strap urges rotation of said eccentric shaft and urges the drummounted on said shaft bodily toward the other one of said drums toincrease the grip on the strap passed therebetween as strap tensionincreases.
 8. The strapping machine set forth in 5, wherein one of saiddrums is mounted on an eccentric shaft, said eccentric shaft being soaligned with respect to the other one of said drums that tension in thestrap urges rotation of said eccentric shaft and urges the drum mountedon said shaft bodily toward the other one oF said drums to increase thegrip on the strap passed therebetween as strap tension increases, andcontrol means for said sealing means responsive to rotation of saideccentric shaft for activating said sealing means.
 9. The strappingmachine set forth in 5, wherein one of said drums is mounted on aneccentric shaft, said eccentric shaft being so aligned with respect tothe other one of said drums that tension in the strap urges rotation ofsaid eccentric shaft and urges the drum mounted on said shaft bodilytoward the other one of said drums to increase the grip on the strappassed therebetween as strap tension increases, said eccentric shaftbeing provided with an arm positioned to move through an angular path asthe eccentric shaft is rotated on its axis in response to bodilymovement of said drums toward one another, rotation of said eccentricshaft causing said arm to actuate said sealing means.
 10. A strappingmachine for applying a plastic strap around an object, said strappingmachine comprising strap-gripping means for holding the leading end ofthe strap encircled about the object and overlapping a supply portion ofthe strap, seal-feeding means for feeding a seal to be sealed around theoverlapping portion of said strap after the strap is in the overlappingposition thereof, tensioning means for tensioning the loop of strap bywithdrawing the supply portion of the strap relative to the leading endof the strap, sealing means for securing together the leading end of thestrap and the adjacent supply portion of the strap to provide a sealjoint therebetween by applying the seal around the overlapped portion ofthe strapping, control mechanism for said sealing means responsive to apredetermined tension in the loop of strap for activating said sealingmeans, control means for said tensioning means responsive to completionof the operation of said sealing means for releasing the tension in thesupply portion of the strap, and said strap-severing mechanism forsevering the supply portion of the strap adjacent to the seal jointafter the tension in the strap has been released and after said sealingmeans has been released from applying the seal around the overlappedportion of the strapping, whereby to provide a cleanly severed free endof the strap adjacent to the seal joint and to provide a cleanly severedleading end of the strap on the supply portion thereof.
 11. Thestrapping machine set forth in 10, wherein the predetermined tension isthe maximum tension attained in the loop of strap by said tensioningmeans.
 12. The strapping machine set forth in 10, wherein said controlmechanism for said sealing means is provided with a time delay means fordelaying the immediate operation of said sealing means when thepredetermined tension has been reached.
 13. The strapping machine setforth in 10, and further including control mechanism for preventing thefeeding of the supply portion of the strap during the formation of theseal joint.
 14. A strapping machine for applying a plastic strap aroundan object, said strapping machine comprising mechanism for guiding theleading end of a length of strap leading from a strap supply and loopedaround an object and overlapping a supply portion of the strap,seal-feeding means for feeding a seal to be sealed around theoverlapping portion of said strap after the strap is in the overlappingposition thereof, tensioning means for tensioning the loop of strap bywithdrawing the supply portion of the strap relative to the leading endof the strap, a blade over which the strap passes, jaws for gripping theleading end of the strap against the blade, said blade having a portionwith transverse grooves formed therein and said jaws forcing thematerial of the strap into the grooves to hold the strap taut during theoperation of said tensioning means, sealing means for securing togetherthe leading end of the strap and the adjacent supply portion of thestrap to provide a seal joint therebetween by applying the seal aroundthe oveRlapped portion of the strapping, control means for saidtensioning means responsive to completion of the operation of saidsealing means for releasing the tension in the supply portion of thestrap, and a movable strap shear means for coacting against anotherportion of said blade for severing the supply portion of the strapadjacent to the seal joint after the tension in the strap has beenreleased and after said sealing means has been released from applyingthe seal around the overlapped portion of the strapping, whereby toprovide a cleanly severed free end of the strap adjacent to the sealjoint and to provide a cleanly severed leading end of the strap on thesupply portion thereof.
 15. The strapping machine set forth in 14,wherein said movable strap shear means is activated by a fluid motor.16. The strapping machine set forth in 14, wherein said movable strapshear means is activated by an air motor.
 17. The strapping machine setforth in 14, and further comprising control mechanism to prevent feedingof strap from the strap supply during strap severing.
 18. A strappingmachine for applying a plastic strap around an object, said strappingmachine comprising strap-gripping means for holding the leading end ofthe strap encircled about the object and overlapping a supply portion ofthe strap, seal-feeding means for feeding a seal to be sealed around theoverlapping portion of said strap after the strap is in the overlappingposition thereof, tensioning means for tensioning the loop of strap bywithdrawing the supply portion of the strap relative to the leading endof the strap, a first fluid motor for operating said strap-grippingmeans and said tensioning means for causing simultaneous actuation ofsaid tensioning means and said strap-gripping means, sealing means forsecuring together the leading end of the strap and the adjacent supplyportion of the strap to provide a seal joint therebetween by applyingthe seal around the overlapped portion of the strapping, a second fluidmotor for operating said sealing means, control mechanism for saidsecond fluid motor responsive to a predetermined tension in the supplyportion of the strap for activating said second fluid motor, controlmeans for said first fluid motor responsive to completion of theoperation of said sealing means for releasing the tension in the supplyportion of the strap, strap-severing mechanism for severing the supplyportion of the strap adjacent to the seal joint, a third fluid motor foroperating said strap-severing mechanism to sever the supply portion ofthe strap, and control mechanism for said third fluid motor responsiveto release of tension in the supply portion of the strap and after saidsealing means has been released from applying the seal around theoverlapped portion of the strapping, for operating said third fluidmotor, whereby to provide a cleanly severed free end of the strapadjacent to the seal joint and to provide a cleanly severed leading endof the strap on the supply portion thereof.
 19. The strapping machineset forth in 18, wherein said first fluid motor is an air motor.
 20. Thestrapping machine set forth in 18, wherein said second fluid motor is anair motor.
 21. The strapping machine set forth in 18, wherein said thirdfluid motor is an air motor.
 22. The strapping machine set forth in 18,wherein said first and third fluid motors are reciprocating air motors.23. A strapping machine for applying a plastic strap around an object,said strapping machine comprising mechanism for guiding the leading endof a supply portion of a length of strap leading from a strap supply andlooped around an object, seal-feeding means for feeding a seal to besealed around the overlapping portion of said strap after the strap isin the overlapping position thereof, first and second cooperating drivedrums positioned to have the supply portion of the strap passingtherebetween, a blade over which the strap passes, jaws for gripping theleading edge of the strAp against the blade, said blade having a portionwith transverse grooves formed therein and said jaws forcing thematerial of the strap into the grooves to hold the strap taut when thejaws are in the strap-gripping position thereof, a first fluid motor forsimultaneously tensioning the loop of strap by withdrawing the supplyportion of the strap relative to the leading end of the strap andactuating said gripping jaws, sealing means for securing together theleading end of the strap and the adjacent supply portion of the strap toprovide a sealed joint therebetween by applying the seal around theoverlapped portion of the strapping, a second fluid motor for operatingsaid sealing means, control mechanism for said second fluid motorresponsive to said first and second cooperating drive drums at apredetermined tension in the supply portion of the strap for activatingsaid second fluid motor, control means for said first fluid motorresponsive to completion of the operation of said sealing means forreleasing the tension in the supply portion of the strap, a movablestrap shear means for coacting against another portion of said blade forsevering the supply portion of the strap adjacent to the sealed joint, athird fluid motor for operating said strap shear means to sever thesupply portion of the strap, and control mechanism for said third fluidmotor responsive to release of tension in the supply portion of thestrap and after said sealing means has been released from applying theseal around the overlapped portion of the strapping for operating saidthird fluid motor, whereby to provide a cleanly severed free end of thestrap adjacent to the sealed joint and to provide a cleanly severedleading end of the strap on the supply portion thereof.